The present disclosure is directed to a double-sided cutting insert. The double-sided cutting insert exhibits a combination of favorable cutting edge strength, and unique cutting edge geometry, thus, allowing milling operations at relatively high feed rates and may be useful in face milling, slot milling, plunge milling, and ramping operations.
Cutting inserts, carbide and other types, are well known in the art. Many indexable cutting inserts are single-handed, either right handed or left handed, due to the geometrical constraints in a rotary machining operation where the cutting tool is rotating against a stationary work piece being ground.
Recently, there have been increasing demands for reduced cost and high productivity in metal machining industries. Two common approaches in the design of indexable carbide cutting inserts, from geometrical point of view, are either to design a double-sided cutting insert, or to design more available cutting edges on a single-sided cutting insert. Double-sided cutting inserts can double the number of available cutting edges, and have cost reduction benefits for both cutting tool end users and cutting tool manufacturers. An ideal solution to a productive indexable cutting insert design can be an indexable cutting insert that has both more available cutting edges and is double-sided. However, the geometric design of a double-sided cutting insert for milling is a more challenging task compared to a traditional single-sided cutting insert, because of the complexity of positioning a double-sided cutting insert in an insert pocket on a cutting tool holder. The difficulty increases as the number of cutting edges increases. Furthermore, the design of a single-handed double-sided cutting insert with more indexable cutting edges for milling operations is even more challenging because the two sides of a single-handed double sided cutting insert may not be a simple mirror image of each other.
In the case of a single-handed double-sided cutting insert with convex cutting edges and conical peripheral surfaces, design is even more challenging due to the difficulties to secure the cutting inserts having convex peripheral profile as compared to commonly used double-sided cutting inserts in a shape of square, triangle or parallelogram, wherein a lateral peripheral surface is planar or perpendicular to a bottom seat face in an insert pocket of a tool holder. A single-sided cutting insert for high feed face milling is disclosed in U.S. Pat. No. 7,220,083, assigned to the assignee of the present invention, and which is hereby incorporated herein by reference, and United States Patent Application Publication No. US 2007/0189864, published Aug. 16, 2007, a continuation patent application of the aforesaid U.S. Pat. No. 7,220,083, which is also assigned to the assignee of the present invention, and which is also hereby incorporated herein by reference. This patent and published patent application disclose a single-sided cutting insert having four convex cutting edges, each connected by a nose corner, and each convex cutting edge having a curved cutting edge region and one or more substantially straight cutting edge regions. The curved cutting edge region has a large radius to facilitate high feed face milling operations. However, this insert is single-sided, thus having only four indexable cutting edges.
Double-sided cutting inserts are disclosed in a number of U.S. patents. For example, U.S. Pat. Nos. 6,929,429; 7,232,279; 7,241,082; 6,921,233; 7,306,409; and 6,543,970. The double-sided cutting inserts described above provide more indexable cutting edges, but the cutting edges of these inserts can be less desirable for high feed milling operations than the cutting edges of the single-sided cutting insert described in the aforesaid United States Patent Application Publication No. US 2007/0189864.
Therefore, it would be desirable to produce a double-sided cutting insert having eight indexable cutting edges, wherein each cutting edge has features to facilitate high feed milling operations as described in the aforesaid United States Patent Application Publication No. US 2007/0189864.